Catheter needle tip shielding device

ABSTRACT

The present invention discloses a catheter instrument  1000  comprising a needle tip shielding device  100,  a catheter hub  200  and a needle unit  300,  wherein the needle unit  300  is provided with connecting means  301  for connection to the catheter hub  200,  and with connecting means  302  for connection to an external device. The needle tip shielding device  100  is comprising a body with a rear side  106,  a front side  107,  an outer surface  108  connecting the rear side  106  and the front side  107,  a hole  102  extending from the rear side  106  to the front side  107,  and a resilient arm  103  extending at an attachment point  105  from the front side  107  of the body; wherein the resilient arm  103  has a resting stale from which it may be forced to yield free passage through the hole  102  in an axial direction of the body, the resilient arm  103  being adapted for clamping a needle tip  304  of a hollow needle  303  extending through the hole  102  in a direction from the rear side  106  to the front side  107,  when being in the resting state.

TECHNICAL FIELD

The present invention relates to a catheter instrument comprising aneedle tip shielding device for the automatic safety shielding of aneedle after its employment for introduction of a catheter tube.

BACKGROUND

The clinical utilization of a pointed hollow needle mounted inside aflexible catheter tube is well known in the medical art for theintroduction of a catheter. In such a medical instrument, the cathetertube is positioned tightly around the needle in such a way as to allowthe needle to slide and telescope along the length of the catheter tube.Before use, the tip of the needle is protruding slightly through theopening of the catheter tube to allow facile penetration through theskin. Upon puncturing of the skin and introduction of the needle, thedistal end of the catheter tube is simultaneously brought into placeinside the desired target body cavity of the patient, such as the insideof a blood vessel, for example a vein. The needle has then done its dutyin assisting the introduction of the catheter and is withdrawn by beingpulled backwards through the catheter. Upon release of the needle, thecatheter is set in its intended working mode extending over a lengthierperiod of time and including, for example, periodical administration orinfusion of fluids or medications in liquid form, the collection ofblood samples and the like.

An unprotected released needle constitutes, however, a serious healthhazard clue to the fact that it may be contaminated with e.g. infectiousagents originating from the patient's blood or other body fluids, incombination with the needle tip's inherent ability to easily penetrateskin. Hence, the medical personnel who are handling the released needlemay acquire the corresponding disease, e.g. HIV or hepatitis, if byaccident contacting it with their skin. In order to circumvent oralleviate the health hazards associated with such a released needleamongst other things, there has been much effort devoted to thedevelopment of various kinds of needle tip protectors with a specialfocus on automatic variants of a type which may be referred to as being“foolproof”.

U.S. Pat. No. 6,616,630 B1, by B. Braun Melsungen A. G. discloses asafety IV catheter comprising a resilient spring clip normallypositioned in the catheter hub. The needle of the safety IV catheterpasses through a hole in the spring clip which allows axial movement ofthe needle. When the needle is in the forward position, i.e. when thesafety IV catheter is ready for use, the presence of the needle forcesparts of the spring clip into a position where these parts locks to theinside of the catheter hub, whereby movement of the spring clip relativethe catheter hub is prevented. As the needle is withdrawn to a pointwhere the tip passes these parts, the spring clip snaps into a positionin which it is blocking access to the to the tip of the needle.Simultaneously, the part of the spring clip that previously locked tothe inside of the catheter hub snap out of this position, wherebymovement of the spring clip relative the catheter hub may occur. As theneedle is further withdrawn, means are provided, e.g. a slot or a crimpon the needle, to lock the spring clip to the needle, whereby the springclip is ejected from the catheter hub together with, and positioned on,the needle.

For various reasons, including e.g. practical, economical and technicalreasons, the above described spring clips, and similar marketedvariants, are today by necessity made of metal and catheter hubs of aplastic material. Disadvantages of the combination of these materials inthis application include the release of e.g. microscopic plastic chipsand metallic particles by the scraping of the metal spring clip againstthe inside of the plastic catheter hub when the former is ejected fromthe latter upon withdrawal of the needle. These chips and particles mayeasily be flushed into the bloodstream of a patient upon normal use ofthe corresponding catheter, and thus represent a serious health hazardto the same.

Spring clips, like the type described above and similar marketedvariants, and needles, are today both by necessity made of metal. Onedisadvantage of the spring clip of this and similar safety IV cathetersis the scraping vibration generated as the needle slides through and onthe spring clip as it is withdrawn. This scraping vibration, which isdue to metal sliding over metal and which can be clearly heard and felt,is highly uncomfortable and worrisome to the patient, who already is inan uncomfortable and exposed situation and may be very anxious.

Furthermore, spring clips, like the type disclosed above, provide poorprotection per se against drops of blood or body fluid that may moveoutwards from the interior of the catheter hub as the needle is removed.Such drops may, for example, spread infectious diseases.

GB2451153(A) by Poly Medicure Ltd discloses a needle safety device foran intravenous catheter apparatus that includes a base capable ofreceiving a needle between opposing jaws attached to the base andcapable of being influenced by the needle. The jaws have a linkconnecting the jaws arranged a distance from the base. The jaws may movebetween an expanded position in which they interact with an obstructionwithin a wing housing of the intravenous catheter apparatus. The jawspermit relative movement of the needle with the base when expanded,close around a needle tip as it passes the jaws, and prevent relativemovement of the needle with the base when the jaws are collapsed.

However, when collapsed, each and one of the jaws do not extend furtherthan maximally to the center axis of the needle. The particular jaw,onto which the tip of the needle is pointing, may thus relatively easyreveal the needle tip if it happens to be bent. In addition, the jawsneed to be forced together with a link. This link represents anadditional part of the device, which increases cost and complicatesproduction of the same.

EP657184(A1) by the BOC Group plc discloses a medical device, forexample, an IV cannula or a syringe which has a hollow needle with asharp distal end for piercing the skin of a patient and includes meansfor protecting the sharp end of the needle after use to minimize thepossibility of accidental needle stick. The means includes a rod mountedfor movement through the needle between a needle end protection positionand a retracted position within the hollow needle, and means formaintaining the rod towards the needle end protection position.

However, since the needle tip is not protected in the protectionposition there is a risk that the needle may cause dermal wounds if theneedle engages the skin close to parallel or at a minor angle towardsthe skin.

Hence, an improved device for automatic shielding of the needle tip of aneedle after its employment for introduction of a catheter tube isdesired.

SUMMARY

It is an object of the present invention, considering the disadvantagesmentioned above, to provide a safety catheter instrument and needle tipshielding device which is devoid of scraping vibrations, or where thesevibrations are reduced, as the needle is withdrawn.

It is another object of the present invention to provide a needle tipshielding device with an improved protection per se against drops ofblood or body fluid that may move outwards from the interior of thecatheter hub as the needle is withdrawn from a safety catheterinstrument.

It is yet another object of the present invention to provide a needletip shielding device which may be withdrawn from a catheter hub with aminimized risk for the generation of internal scratches on the interiorsurface of the latter.

It is yet another object of the present invention to provide a needletip shielding device which may be withdrawn from a catheter hub with aminimized risk for the generation of loose particles, such as particlesof plastic or metal.

It is yet another object of the present invention to provide a needletip shielding device with improved safety with regard to the shieldingof the needle tip.

It is yet another object of the present invention to provide a needletip shielding device which may be easily manufactured at a low cost.

These and other objects, which will appear from the followingdescription, have now been achieved by a device according to one aspectof the present invention which comprises a plastic needle tip shieldingdevice comprising a body with a rear side, a front side, an outersurface connecting the rear side and the front side, a hole extendingfrom the rear side to the front side, and a resilient arm extending atan attachment point from the front side of the body; wherein theresilient arm has a resting state from which it may be forced to yieldfree passage through the hole in an axial direction of the body, theresilient arm being adapted for clamping a needle tip of a hollow needleextending through the hole in a direction from the rear side to thefront side, when being in the resting state; and wherein any straightimaginary line extending longitudinally through the hole in the axialdirection of the body coincides with a point on the surface of theresilient arm, or an elongation thereof, when the resilient arm is inthe resting state.

According to another aspect of the present invention, the needle tipshielding device may be shaped as a circular or distorted cut cone orcylinder.

According to yet another aspect of the present invention, the needle tipshielding device may be provided with a back-hooking elongation, theresilient arm together with the back hooking elongation thereof may havean L-shaped form; wherein the any straight imaginary line coincides witha point on the surface of the resilient arm in between the attachmentpoint and an inner corner in the L-shaped form of the resilient arm,when the resilient arm is in the resting state; and wherein the anystraight imaginary line coincides with a point on the surface of theback-hooking elongation, or with a point on the surface in between theattachment point and the corner, when the resilient arm is clamping theneedle tip in cooperation with the back-hooking elongation.

According to yet another aspect of the present invention, the resilientarm of the needle tip shielding device, or any elongation thereof, mayhave a maximum of one external point of contact, the point of contactbeing a contact with any part of the hollow needle, when used.

According to yet another aspect of the present invention, the innerdiameter of the hole may be equal to or slightly larger than the outerdiameter of the shaft of the hollow needle to provide a sliding anddirecting engagement between the shaft and the needle tip shieldingdevice.

According to another aspect of the present invention, the needle tipshielding device may comprise a body shaped as a circular or distortedcut cone or cylinder with a rear side, a front side, an outer surfaceconnecting the rear side and the front side, a hole extending from therear side to the front side, and a resilient arm extending at anattachment point from the front side of the body; wherein the resilientarm has a resting state from which it may be forced to yield freepassage through the hole in an axial direction of the body, theresilient arm together with a back-hooking elongation thereof having anL-shaped form for clamping a needle tip of a hollow needle extendingthrough the hole in a direction from the rear side to the front side;wherein any straight imaginary line extending longitudinally through thehole in the axial direction of the body coincides with a point on thesurface of the resilient arm in between the attachment point and aninner corner in the L-shaped form of the resilient arm, when theresilient arm is in the resting state; wherein any of the beforementioned straight imaginary lines coincides with a point on the surfaceof the back-hooking elongation, or with a point on the surface inbetween the attachment point and the corner, when the resilient arm isclamping and thus protecting the needle tip in cooperation with theback-hooking elongation; and wherein the resilient arm or theback-hooking elongation has a maximum of one external point of contact,the point of contact being a contact with any part of the hollow needle,when used.

According to another aspect of the present invention, the needle tipshielding device may be made of a molded plastic material. In thisrespect, the needle tip shielding device may be molded, such as forexample injection molded, into one homogenous piece and/or one integralunit, without interfaces in between the different parts thereof.

According to yet another aspect, the outer surface may be provided withat least one protuberance.

According to yet another aspect, the rear side may be provided with acone-shaped elevation through which the hole is extending.

According to yet another aspect, the rear side may be larger than thefront side to form an inclination of the outer surface within the rangefrom 0° to 10°.

According to yet another aspect, the length of the back-hookingelongation, measured from the corner to the most protruding part, may be0.5 to 6 times the diameter of the hole.

According to yet another aspect, the angle inside the corner may bewithin the range from 60° to 110°.

According to yet another aspect, the body may be elliptic.

According to yet another aspect, the resilient arm of the needle tipshielding device may be provided with a back-dragging preventingelongation for prevention of unintentional movement of the needle tipshielding device in the direction from the front side to the rear side,when the needle tip shielding device is mounted in a catheterinstrument.

According to yet another aspect, the front side of the needle tipshielding device may be provided with a longitudinal arm for additionalprotective shielding of the needle tip or the hollow needle.

According to yet another aspect of the present invention, there isprovided a catheter instrument comprising the needle tip shieldingdevice, a catheter hub and a needle unit; wherein the needle unit isprovided with connecting means for connection to the catheter hub, withconnecting means for connection to an external device, and is fixedaround the rear end of the hollow needle; and wherein the catheter hubis connected to a catheter extending longitudinally in the samedirection as the hollow needle when the needle unit is connected by theconnecting means to the catheter hub.

Further features of the invention and its embodiments are set forth inthe ended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which the inventionis capable will be apparent and elucidated from the followingdescription of non-limiting embodiments of the present invention,reference being made to the accompanying drawings, in which

FIG. 1 is a cross section view from the side of a catheter instrumentaccording to one embodiment in the ready mode, i.e. before its use forthe introduction of a catheter tube, comprising a needle tip shieldingdevice according to one embodiment, a catheter hub and a needle unit,according to an embodiment of the present invention;

FIG. 2 is a cross section view from the side of a needle tip shieldingdevice according to one embodiment fitted inside a catheter hub with ahollow needle withdrawn to the point where an expansion region reaches acontact point of a resilient arm, according to an embodiment of thepresent invention;

FIG. 3 is a cross section view from the side of a needle tip shieldingdevice according to one embodiment fitted inside a catheter hub with ahollow needle withdrawn to the point where an expansion region reaches ahole, whereby further backwards movement of the hollow needle relativethe catheter hub is prevented without disconnection of the needle tipshielding device from the catheter hub, according to an embodiment ofthe present invention;

FIG. 4 is a cross section view from the side of a needle tip shieldingdevice according to one embodiment disconnected from the catheter hub,with a hollow needle pushed forward with the rear end of an expansionregion a distance D1 from the most forward edge of a hole, whereby aneedle tip coincidences with a corner, according to an embodiment of thepresent invention;

FIG. 5 is a perspective view of a needle tip shielding device accordingto one embodiment comprising a body with a circular rear side, acircular front side, an outer surface connecting the circular rear sideand the circular front side, the circular hole extending from thecircular rear side to the circular front side, and a resilient armextending from the front side of the body, according to an embodiment ofthe present invention;

FIG. 6 is a partial cross section view from the side of a needle tipshielding device according to one embodiment, mounted in a catheter hubat a region where the tilt angle is practically 0° and wherein aresilient arm is provided with a back-dragging preventing elongation andwherein a catheter hub is provided with a catheter hub bump, accordingto an embodiment of the present invention; and

FIG. 7 is a perspective view of one embodiment of a needle tip shieldingdevice comprising a front side provided with a cone shaped elevation, anouter surface provided with four (two of these not visible in thefigure) evenly spread protuberances and a longitudinal arm extendingfrom the front side, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described in more detailbelow with reference to the accompanying drawings in order for thoseskilled in the art to be able to carry out the invention. The inventionmay, however, be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. The embodiments do not limit the invention, but theinvention is only limited by the appended patent claims. Furthermore,the terminology used in the detailed description of the particularembodiments illustrated in the accompanying drawings is not intended tobe limiting of the invention.

Embodiments of the present invention will now be described below withreference to FIGS. 1 to 7.

Referring to FIG. 1, there is provided a catheter instrument 1000comprising a needle tip shielding device 100, a catheter hub 200 and aneedle unit 300. The needle unit 300 is provided with connecting means301 for connection to the catheter hub 200, and with connecting means302 for connection to an external device, for example a syringe or thelike. It is mechanically and hermetically fixed as known in the art,such as molded or glued, around the rear end of a hollow needle 303,whereby liquid passage is allowed in both directions, from the rear endof the needle unit 300 to and through a needle tip 304 of the hollowneedle 303. The hollow needle 303 may be made of metal and of a typecommonly used and well known in the medical art to penetrate the skin ofa patient.

The needle tip shielding device 100 is fitted inside the catheter hub200 so that the outer surface of the former is contacting the innersurface of the latter, via a catheter hub contact area. Movement of theneedle tip shielding device 100, relative the catheter hub 200, may berestricted by means of at least one protuberance 101, comprising thecatheter hub contact area, located on the outer surface 108 of theneedle tip shielding device 100. Protuberance 101 is making acorresponding imprint in, and where it contacts, the inner surface ofthe catheter hub 200. The hollow needle 303 is longitudinally movablethrough a hole 102 in the needle tip shielding device 100. The hole 102has a diameter adapted for the hollow needle 303 to be able to slidetherein. The diameter of the hole 102 may, for example, be slightlylarger that the outer diameter of the hollow needle 303, or the same.The hollow needle 303 is provided with an expansion region 305 near theneedle tip 304. The expansion region 305 is a region on the hollowneedle 303 where the effective diameter is larger than elsewhere on theneedle in the direction towards the rear hollow needle 303. An increasein the effective diameter of the hollow needle 303 by expansion region305 has the effect that this region is not movable through the hole 102.

The needle tip shielding device 100 is provided with a resilient arm103, which is held out of its three dimensional equilibrium state, i.e.its normal resting position or resting state, by the outer surface ofthe hollow needle 303. The hollow needle 303 is, despite its contactwith the resilient arm 103, longitudinally movable as it is arranged toslide on the same. The catheter hub 200 is connected to a catheter 201,which extends longitudinally in the same direction as the hollow needle303. The catheter 201 is preferable flexible and of a type commonly usedand well known in the medical art. The inner diameter of the catheter201 may be slightly larger than the outer diameter of the hollow needle303 and arranged so that the latter, as well as expansion region 305,may slide inside the former.

In the ready mode, i.e. before its use for the introduction of acatheter tube, the following characteristics of catheter instrument 1000are valid: (i) Needle unit 300 is connected by connecting means 301 tothe catheter hub 200. (ii) The hollow needle 303 is extending throughthe hole 102 of the needle tip shielding device 100, which is fittedinside the catheter hub 200, whereby movement of the needle tipshielding device 100 relative the catheter hub 200 is restricted. Thehollow needle 303 is contacting the resilient arm 103 whereby this isforced out of its normal resting position. (iii) The hollow needle 303is further extending through catheter 201 so that the needle tip 304 isprotruding slightly past the opening of the catheter 201 in order tofacilitate penetration of the skin of a patient.

When in ready mode, the catheter instrument 1000 may be used by a user,such as a nurse or other medical personnel, for the introduction of acatheter tube, such as catheter 201, in accordance with the followingsequential steps: (i) Penetration of the skin of a patient by means ofneedle tip 304, followed by insertion of the catheter 201 so that itsopening is located in the desired body cavity, such as the inside of avein. (ii) Fastening of the catheter hub 200 on the skin of the patientby means well known in the art, such as with medical tape or the like.(iii) Disconnection of connecting means 301, followed by withdrawal ofthe hollow needle 303 by holding onto and pulling the needle unit 300backwards until the needle tip shielding device 100 is disconnected,whereby the resilient arm 103 of the needle tip shielding device 100 isprotecting the needle tip 304 so that it cannot penetrate skin byaccident.

With reference to FIGS. 2, 3 and 4, below follows a detailed descriptionof the various events that occur upon withdrawal of the hollow needle303 according to (iii) above:

When the hollow needle 303 has been withdrawn to the point whereexpansion region 305 reaches the contact point of the resilient arm 103,the latter may bend away slightly to allow easy passage of the formerupon a slight increase in the force of withdrawal (FIG. 2). If theexpansion region 305 is of a particular type and located on the hollowneedle 303 such that the resilient arm does not come in contact with anyarea with increased effective diameter, the resilient arm does not haveto bend away slightly. Examples of such an expansion region 305 includea protruding bump, e.g. a butt weld, which is facing away from thecontact point of the resilient arm 103 on the hollow needle 303.Examples of other possible expansion regions 305 include a crimp or anyother protruding distortion as well known in the art.

Further withdrawal of the hollow needle 303, to the point where theneedle tip 304 passes the contact point of the resilient arm. 103,results in that the latter strives toward its normal resting position,which is such that a part of the resilient arm 103, or an extensionthereof, is in front of the needle tip 304 (FIG. 3). The restingposition of the resilient arm 103 is such that the needle tip 304 willalways project, in the longitudinal direction of the hollow needle 303,onto a point of the surface of the resilient arm 103 which is positionedbetween a corner 104 and the attachment point 105 of the resilient arm103 independent of the degree of rotation of the hollow needle 303around its longitudinal axis. The needle tip 103 is thus clamped andprotected by the resilient arm 103.

When drawn backwards beyond this point, the hollow needle 303 may not bepushed in the forward direction again without being hindered, by theresilient arm 103, or an extension thereof. Hence, if a user tries topush the hollow needle 303 forwards, the needle tip 304 may penetrateslightly into the resilient arm 103. Preferably the resilient arm 103 isarranged so that this penetration occurs in the corner 104 (FIG. 4).

Even further withdrawal of the hollow needle 303, to the point where theexpansion region 305 reaches the hole 102, results in that the hollowneedle 303 engages with, i.e. gets stuck in, in the needle tip shieldingdevice 100 (FIG. 3). Additional increase in the force of withdrawal ofthe hollow needle 303 results in that the needle tip shielding device100 disconnects from the catheter hub 200. The hollow needle 303 isthereby released from the catheter hub 200 together with the needle tipshielding device 100, which is effectively clamping the needle tip 304and protecting a user from accidental contact with the same. The forceneeded to disconnect the needle tip shielding device 100 from thecatheter hub 200 is, amongst other factors, depending on the anglebetween an imaginary line L1, which is equivalent with the extension ofthe hollow needle 303 and the center of the hole 102, and an imaginaryline L2, which is a straight line extending in the same plane as L1 thatcoincides with two points on the surface of the needle tip shieldingdevice 100 being in contact with the inner surface of the catheter hub200, the points being located outside the surface of the protuberance101 (FIG. 3). Preferably this angle is such that the needle tipshielding device 100 is not disconnected from the catheter hub when thehollow needle 303 is withdrawn until the expansion region 305 reachesthe hole 102. The needle tip shielding device 100 is, however,preferably easily disconnected when the expansion region 305 reaches thehole 102, such as with, for example, a gentle jerk backwards. When thehollow needle 303 and the needle tip shielding device 100 have beenreleased from the catheter hub 200, or when the needle tip shieldingdevice 100 is fitted inside the catheter hub 200 and the needle tip 304is clamped by the resilient arm 103, or an extension thereof, the hollowneedle 303 might be pushed forward so that the rear end of the expansionregion 305 is moved forward a distance D1 from the most forward edge ofthe hole 102, during which the needle tip 304 may slide on the surfaceof the resilient arm 103 until it coincides with the corner 104 (FIG.4).

The Catheter Instrument 1000

Connecting means 301 and 302 may independently be selected from variousconnection types allowing a user to connect and disconnect the needleunit 300 from the catheter hub 200, and the needle unit 300 from theexternal device, respectively, as desired. Examples of such connectiontypes include Luer-Lok®, Luer-Slip®, and various types of bayonetsockets or the like, as well known in the art. Preferably, connectingmeans 301 and 302, in particular connecting means 302, are air tight sothat no gas or liquid, such as blood or any other body liquid, may pass.

With reference to FIG. 4, according to one embodiment, the location ofthe expansion region 305 on the hollow needle 303 is selected such thatthe distance D1 is minimized while still allowing the resilient arm 103,or an extension thereof, to clamp the needle tip 304 when the hollowneedle 303 is withdrawn.

According to one embodiment, the catheter hub 200 may be provided withadditional devices and the like to facilitate its placement and optimizeits use, as well known in the art. For example, it may be provided withvalves, gaskets, fastening devices, means for drying blood residues ofthe needle, and the like.

The Needle Tip Shielding Device 100

With reference to FIG. 5, according to one embodiment of the invention,the needle tip shielding device 100 comprises a body with a rear side106, a front side 107, an outer surface 108 connecting the rear side 106and the front side 107, a hole 102, preferably being circular, extendingfrom the rear side 106 to the front side 107, and a resilient arm 103extending from the front side 107 of the body. The rear side 106 and thefront side 107 may be essentially flat and may be essentially parallelto each other. The hole 102 may extend essentially perpendicular to theplane of the rear side 106, and to the plane of the front side 107. Thehole 102 is preferably positioned essentially at the center of the rearside 106, and at the center of the front side 107. The straightimaginary line L2 is coinciding with a point P1 at the edge between therear side 106 and the outer surface 108, and with a point P2 at theshortest possible distance from point P1 at the edge between the frontside 107 and the outer surface 108. At any pair of points P1 and P2, thepart of line L2 extending from P1 to P2 preferably essentially coincideswith the outer surface 108. The straight imaginary line L1 extendinglongitudinally through the center of the hole 102 is preferablyessentially coinciding with the plane of any line L2. Any imaginarystraight line, which is parallel with L1 and extending longitudinallythrough the hole 102, coincides with a point at the surface in betweenthe attachment point 105 (not shown in FIG. 5) and the corner 104 of theresilient arm 103, when the resilient arm is in its resting state. Theattachment point 105 is the edge which defines the transition betweenthe front side 107 and the side of the resilient arm 103 which isclosest to the hole 102. The corner 104 defines a sudden bend of theresilient arm 103 towards the plane of the front side 107, when theresilient arm 103 is in its resting state. Thus, the resilient arm 103attains an L-shaped form, where the horizontal line of the L correspondsto a back-hooking elongation 110 of the resilient arm 103. The shape ofthe needle tip shielding device 100 according to the present inventionhas, in comparison to corresponding devices of the prior art, theadvantage that it will act as a shield at the moment it disconnects fromthe catheter hub 200. Thereby it provides excellent protection per seagainst drops of blood or body fluid that may move outwards from theinterior of the catheter hub 200 as the hollow needle 303 is removed.

Preferably, the resilient ann 103 is dimensioned, and attached at aposition on the front side 107, such that it or the back-hookingelongation 110 may never contact the inner surface of the catheter hub200 independent of the position of the hollow needle 303. Such a contactwould potentially adventure the intended placement of the needle tipshielding device inside the catheter hub 200.

Preferably, the area of the back-hooking elongation 110 is fullycovering the projecting area of the hole 102 when the needle tip 304 isclamped in the corner 104, i.e. protected, while the resilient arm 103is maximally forced out of its resting state (as dependant on therotation of the hollow needle 303 whereby the needle tip 304 attainsdifferent coordinates). This minimizes the risk of uncovering the needletip 304 on the event that the resilient arm 103 gets bent by e.g. asideways applied external force. Such a setup is not possible when morethat one arm or jaw, corresponding to the resilient arm 103, is used incollaboration as they counteract each other in this regard.

According to one embodiment, the needle tip shielding device 100 has a.circular shape, such that the rear side 106 and the front side 107projects a circle from a view along the direction of the hollow needle303.

According to one embodiment, the needle tip shielding device 100 has anelliptic shape, such that the rear side 106 and the front side 107projects an ellipse from a view along the direction of the hollow needle303.

According to one embodiment, the hole 102 is centered in the rear side106 and in the front side 107.

According to one embodiment, the rear side 106 has a diameter in therange of 3 to 6 mm, preferably 3.9 to 4.3 mm, and even more preferred4.1 to 4.15 mm.

According to one embodiment, the rear side 106 is provided with acone-shaped elevation 109 through which the hole 102 is extending. Theeffective length of the hole 102 is thereby increased which, forexample, allows a better guidance of the hollow needle 303 withouthaving to increase the area of the outer surface 108 by increasing thedistance between P1 and P2. Furthermore, the cone-shaped area might beprovided with means known in the art, such as a circular scraper, whichcleans off residues of e.g. blood from the hollow needle 303 as this iswithdrawn.

According to one embodiment, the inner diameter of the hole 102 may beequal to or slightly larger than the outer diameter of the shaft of thehollow needle 303 to provide a sliding and directing engagement betweenthe shaft and the needle tip shielding device 100.The inner surface ofthe hole 102 serves as a needle shaft contact area, in contrast to aneedle shaft contact line in the metal clips according to known art, forcontact with the outer surface of the shaft of the hollow needle 303,i.e. a sliding and directing engagement. This contact area may bemaintained, while minimizing product material, i.e. product volume, byarranging the contact area fully or partly on the inside of the coneshaped elevation 109.The needle shaft contact area does not necessarilyhave to be a contact surface in the entire contact area, as long as thecontact area substantially prevents a needle shaft positioned throughthe needle tip shielding device from swaying/wobbling in such way thatthe needle tip departs from the central axis of the hole 102.Preferably, the contact area is arranged such that a maximal contactwith needle shaft is achieved without preventing the sliding of thehollow needle 303 through the needle tip shielding device 100. Theneedle shaft contact area may be an area of the needle tip shieldingdevice 100 that surrounds and contacts the needle shaft, i.e. a hole 102through which the hollow needle 303 runs. The inside surface of the hole102, i.e. the needle shaft contact area, may be smooth, rough orprovided with suitable shapes that contact the needle shaft. In general,the prevention of swaying/wobbling of the hollow needle 303 is betterthe longer the needle shaft contact area extends in the direction of thehollow needle 303. The extension of the needle shaft contact area, i.e.the longitudinal extension of the hole 102, is preferably as long aspossible without adventuring any other intended functions of the needletip shielding device. For example, the needle shaft contact area maypreferably not be extended to such a degree that a simultaneous increasein the contact area with the inside of the catheter hub 200 results inthat the needle tip shielding device 100 becomes unacceptable difficultto withdraw from the same. In this case, it is instead preferred toincrease the extension of the cone shaped elevation 109. The cone shapedelevation 109 may, when positioned on the front side, not be extended tosuch a degree that the intended function of the resilient arm 103 isadventured. The extension of the needle shaft contact area may, forexample, be 1 mm to 10 mm. Preferably, the relationship between theouter diameter of the shaft of the hollow needle 303 and the innerdiameter of the hole 102 is such that the hollow needle 303 may easilyslide therein when it is withdrawn or pushed forward, yet with a minimaldifference between these diameters so that there is a minimal gap. Sucha minimal difference, i.e. gap, will provide an adequate and optimalguidance of the hollow needle 303, and thus prevent undesired movementof the hollow needle 303 and the needle tip 304 in a directionperpendicular to the longitudinal direction of the hole 102 as thehollow needle 303 is pushed forwards or withdrawn.

According to one embodiment, the front side 107 may be provided with thecone-shaped elevation 109 (FIG. 7). The cone shaped elevation 109 thenextends forward towards the needle tip, when the needle tip shieldingdevice is arranged on a needle shaft. It is also possible to arrange thecone shaped elevation on the rear side 106, such as disclosed in FIG. 1.The arrangement, e.g. positioning and dimensions, of the resilient arm103 and the cone shaped elevation is such that the intended function ofthe resilient arm 103 is not adventured. Thus, the resting position ofthe resilient arm 103 may be such that the needle tip 304 will alwaysproject, in the longitudinal direction of the hollow needle 303positioned in the hole 102, onto a point of the surface of the resilientarm 103 which is positioned between a corner 104 and the attachmentpoint 105 of the resilient arm 103 independent of the degree of rotationof the hollow needle 303 around its longitudinal axis. When thecone-shaped elevation 109 is positioned on the front side 107, the rearside 106 is preferably essentially flat. This allows for facile assemblyof the needle tip shielding device 100 in the catheter hub 200 bypressing it into the same by employment of a tool which is contact withessentially the entire surface of the rear side 106.

According to one embodiment, the needle tip shielding device 100 isprovided with the aforementioned. protuberance 101. located on the outersurface 108. The protuberance 101 will make an imprint in thesurrounding material of the catheter hub 200 when the needle tipshielding device 100 is positioned therein. The mechanical interactionbetween the protuberance 101 and the catheter hub 200, and thecorresponding imprint caused by the former, will reduce the risks ofunintentional disconnection of the needle tip shielding device 100 fromthe catheter hub 200.

According to one embodiment, the protuberance 101 is an annularprotuberance extending in a continuous loop around the outer surface108.

According to one embodiment, the protuberance 101 is an annularprotuberance extending in a continuous loop around the outer surface108, and being located in a plane perpendicular to L1.

According to another embodiment, the protuberance 101 may be asingularity or a plurality of protuberances independently selected fromthe group consisting of dots, straight elongated shapes, curvedelongated shapes, V-shapes, and any other shape known in the art to makean imprint in an object in order to prevent relative movement versusthis, such as the shapes on the surface of a tire optimized for use onsoft ground.

According to one embodiment, the protuberance 101 may be made of amaterial with a hardness which is greater that the hardness of the innersurface of the catheter hub 200, in order to effectively accomplish animprint in the latter. Preferably, the protuberance 101 is made of thesame material as the rest of the needle tip shielding device 100, inorder to allow for a facile and economically advantageous production ofthe same.

According to one embodiment, the type, multiplicity and dimension ofprotuberance 101 is selected such that no unintentional disconnection ofthe needle tip shielding device 100 from the catheter hub 200 may occur,yet allowing facile intentional disconnection when the hollow needle 303is withdrawn. For example, the protuberance 101 may be an annularprotuberance extending in a continuous loop around the outer surface 108with a height in the range of 0.05 to 0.3 mm from the same.

According to one embodiment, the protuberance 101 may be a plurality ofprotuberances on the outer surface 108 (FIG. 7). These may begin at, orclose to, the corner between the rear side 106 and the outer surface 108and extend in a plane essentially perpendicular to the plane of the rearside 106 and/or the front side 107, toward the front side 107.Preferably, they are evenly spread along the extension of the outersurface 108. Their extension along the outer surface 108 may be 10 to95% of the distance between the rear side 106 and the front side 107along the outer surface 108. Preferably, the endings being closest tothe front side 107 consists of a smooth slope to allow facile insertionin a catheter hub 200. The plurality of protuberances on the outersurface 108 may have a height in the range of 0.01 to 0.3 mm, preferably0.03 to 0.1 mm, and more preferred 0.04 to 0.06 mm, from the same. Theplurality of protuberances on the outer surface 108 may consist of 1 to20 individual protuberances, preferably 2 to 12, which may be of thesame or of different lengths and/or heights. Preferably, they are ofequal length and height.

According to one embodiment, the inclination of the outer surface 108 ofthe needle tip shielding device 100, i.e. the angle between lines L1 andL2, is within in the range from 0° to 10°, preferably in the range from4° to 8°, and even more preferred 6°.Preferably, the inclination of theouter surface 108 is essentially the same as the inclination of thecatheter hub 200 where the needle tip shielding device 100 is mountedwhen the catheter instrument 1000 is in the ready mode. This maximizesthe contact surface between the outer surface 108 and the inside of thecatheter hub 200, whereby accidental detachment of the needle tipshielding device 100 from the catheter hub 200 is hindered.

According to one embodiment, the inclination of the outer surface 108 ofthe needle tip shielding device 100, i.e. the angle between lines L1 andL2, is the same as the angle used in well known or standardizeddetachable conical fittings, such as fittings used for syringes, e.g.the Luer taper.

According to one embodiment, the needle tip shielding device 100 is madeof a plastic material. Preferably, the plastic material has a suitablecombination, for its intended purpose, of tenacity, rigidity, fatigueresistance, elasticity, and creep deformation resistance. The selectionof a suitable plastic material may easily be made by the one skilled inthe art. The one skilled in the art may also perform standardexperiments in order to screen a range of plastic materials, whereby asuitable plastic material may be selected on the basis of the results ofsuch experiments. A suitable plastic material has a high creepdeformation resistance, i.e. it has a low tendency to slowly move ordeform permanently under the influence of an applied external pressure.Hence, a catheter instrument, such as the catheter instrument 1000 ofthe present invention, comprising a needle tip shielding device 100 withprotuberance 101, may be stored in the assembled ready mode for aprolonged time without extensive creep deformation of protuberance 101,which would otherwise make the needle tip shielding device 100 moreprone to involuntary disconnection from the catheter hub 200. A suitableplastic material has, furthermore, a suitable elasticity and highthree-dimensional memory to allow for the resilient arm 103 to retainits resting state and clamp the needle tip 304 even after prolongedstorage, during which the resilient arm 103 has been forced out of thisstate. In addition, the tenacity of the plastic material is preferablysuch that the needle tip 304 may penetrate slightly into, but notthrough the same. The needle tip shielding device 100 may be made of amolded plastic material. Due to the specific configuration of thedifferent parts of the needle tip shielding device 100 according to theembodiments of the present invention, the needle tip shielding device100 may be molded, such as injection molded, into one homogenous pieceand/or one integral unit, without interfaces in between the differentparts thereof. Thus, advantageously, after production by any suitablemolding procedure as known in the art, such as injection molding, allnecessary parts of the needle tip shielding device 100 of the inventionare already integrated without the need for costly and time consumingassembly of different separate parts.

An advantage of the use of a plastic material for the construction ofthe needle tip shielding device 100, in comparison to e.g. metal, is thegreater freedom of variation of various details of the same. Forexample, a plastic needle tip shielding device 100 according to theinvention may be more conveniently molded than the correspondingmetallic article. Another advantage includes the possibility tocolour-code a plastic needle tip shielding device 100 according to theinvention, for example according to the needle size. Yet anotheradvantage of a plastic needle tip shielding device 100 according to theinvention is the fact that the needle tip 304 may penetrate slightlyinto the corner 104 of the resilient arm 103. This represents an“active” and safer shielding principle, in comparison to “passive”shielding of the prior art, whereby the resilient arm 103 is evenfurther locked onto the needle tip 304 and hence additionally restrictedfrom movement out of the safe position. Yet another advantage of aplastic needle tip shielding device 100 according to the invention isthe fact that a metallic needle sliding through the hole 102, and on theresilient arm 103, does not give rise to a scraping vibration and soundof the uncomfortable type related to a metal needle sliding on and/orthrough a metal clip. Yet another advantage of a plastic needle tipshielding device 100 according to the invention is the higher chemicalinertness and/or resistance, in comparison to metal, towards e.g.corrosion and reaction with chemicals that might leak from the plasticsurrounding constituted by a catheter hub and comprising silicon gasketsand the like. Yet another advantage of a needle tip shielding device100, like a plastic needle tip shielding device 100, according to theinvention, is that it may be molded and produced in one functionalpiece, i.e. it does not have to be assembled by the combination of morethan one separate article like other corresponding devices of the priorart. Hence, a reduction in the cost of production is resulting. Yetanother advantage of a plastic needle tip shielding device 100 accordingto the invention is the highly reduced tendency, in comparison to metal,of release of e.g. microscopic plastic chips by the scraping of theplastic catheter hub when the needle tip shielding device 100, or acorresponding device, is ejected from the former upon withdrawal of theneedle. Accordingly, the tendency for formation of scrape marks, whichmay result in leakage through the affected connector, is greatlyreduced.

According to one embodiment, the needle tip shielding device 100 is madeof a thermoplastic polymer comprising crystalline and amorphousalternating regions.

According to one embodiment, the needle tip shielding device 100 is madeof a plastic material selected from the group consisting of POM, PBTP,LCP, PA, PSU, PEI, PC, and PPO/SB.

According to one embodiment, the needle tip shielding device 100 is madeof a thermoplastic elastomer selected from the group consisting of astyrenic block copolymer, a polyolefinic mixture, an elastomeric alloy,a thermoplastic polyurethane, a thermoplastic copolyester, and athermoplastic polyamide.

According to one embodiment, the needle tip shielding device 100 is madeof a plastic material selected from the group consisting of Styroflex®,Kraton®, Pellethane®, Pebax®, Arnitel®, Hytrel®, Dryflex®, Santoprene®,Geolast®, Sarlink®, Forprene®, Alcryn®, and Evoprene®.

According to one embodiment, the needle tip shielding device 100 is madeof a plastic material selected from the group consisting of medicalgrade liquid crystal polymer, for example Vectra® LCP, polyethylene, andultra high molecular weight polyethylene.

According to one embodiment, the needle tip shielding device 100 is madeof polysulfon or polyoxymetylen.

According to one embodiment, the angle inside the corner 104 is withinthe range from 60° to 110°, preferably 80° to 100°, more preferred 85°to 95°, and most preferred 90°.

According to one embodiment, the length of the back-hooking elongation110, measured in its elongation from the corner 104 to the mostprotruding part, is at least 0.5 times the diameter of the hole 102,such as 0.5 to 6 times the diameter of the hole 102. It is preferablydimensioned such that no part of the resilient arm 103 is brought incontact with the inner surface of the catheter hub 200 at any locationof the hollow needle 303 when the needle tip shielding device 100 ismounted in the catheter hub 200.

According to one embodiment, the back-hooking elongation 110 maycomprise a groove with a partial circular shape, as well known in theart, provided and dimensioned to guide and allow the hollow needle 303to slide thereon when withdrawn.

According to one embodiment, the resilient arm 103 may be dimensionedsuch that its most protruding part when being forced out of its restingposition by the hollow needle 303 is in the range of 0.3 to 3 times thediameter of the front side 107, as measured from the attachment point105.

According to one embodiment, the width and placement of the resilientarm 103 is such that no part of the resilient arm 103, or theback-hooking elongation 110, is brought in contact with the innersurface of the catheter hub 200 at any location of the hollow needle303.

According to one embodiment, the width of the resilient arm 103 is inthe range of 0.2 to 0.9 times the diameter of the front side 107 andselected such that it can not be bent aside to expose the needle tip 304under normal circumstances.

According to one embodiment, the thickness and the material of theresilient arm 103 are selected such that the hollow needle 303 may neverpenetrate through the resilient arm 103 by a user under normalcircumstances.

With reference to FIG. 6, according one embodiment, the resilient arm103 may be provided with a back-dragging preventing elongation 111,extending in a direction being within an angle of 0° to 45° opposite thedirection of the back-hooking elongation 110. Preferably, the needle tipshielding device 100, when provided with the back-dragging preventingelongation 111, is mounted in the catheter hub 200 at a region 203 wherethe tilt angle is practically 0°, i.e. the angle between the line L1 andthe line L2, in combination with the same inclination of the outersurface 108. The outer surface 108 may be provided with a protuberance101, but this is not necessary at a low tilt angle, such as 0°. At sucha low tilt angle, such as 0°, the needle tip shielding device may beheld in place in the catheter hub 200 entirely by the friction betweenthe outer surface 108 and the inner surface of the catheter hub 200.Furthermore, the material, of which the needle tip shielding device 100is constructed, may be selected from a greater variety of materialssince an imprint in the catheter hub 200 does not have to be made, ascompared to the case with the existence of a protuberance 101.Preferably, the tilt angle of the catheter hub 200 is greater than 0°,such as 6°, in the region immediately behind, i.e. corresponding to theangle between L1 and L3 and being in the direction towards the rear endof the hollow needle 303, respectively, in order for the needle tipshielding device 100 to be easily removed from the catheter hub 200 whendesired. The catheter hub 200 is provided with an annular catheter hubbump 202, extending around the inner surface of the catheter hub 200 inbetween the placement of the needle tip shielding device 100 and theback-dragging preventing elongation 111. When the hollow needle 303 ispositioned in a forward direction, the back-dragging preventingelongation 111 is forced into a position so that the most extended partof the same is coinciding with point on an imaginary line L5, which isparallel with L1. L5 is coinciding with a point located on the catheterhub bump 202. In this state, the needle tip shielding device 100 isprevented from backwards unintentional movement as the back-draggingpreventing elongation 111 would engage with, and get stuck on, thecatheter hub bump 202. When the needle tip 304 has been withdrawn to thepoint where it is clamped by the back-hooking elongation 110 and/or theresilient arm 103, L5 is not coinciding with any point located on thecatheter hub bump 202, hence, the needle tip shielding device 100 may beremoved from the catheter hub 200. The back-dragging preventingelongation 111 and the catheter hub bump 202 have the function of asafety system which prevents the needle tip shielding device 100 fromcoming out of the catheter hub 200 in the case of an unintentionaldisconnection of the former from the inner wall of the latter.

With reference to FIG. 7, according to one embodiment, the front side107 may be provided with a longitudinal arm 112 for additionalprotective shielding of the needle tip 304 or the hollow needle 303.Advantages of the longitudinal arm 112 include, for example, additionalreduction of the risk for unintentional contact with e.g. the shaft ofthe hollow needle 303, which may be contaminated with e.g. blood, afterdisconnection of the needle tip shielding device 100 from the catheterhub 200. The longitudinal arm 112 is preferably arranged on the frontside 107 such that it faces the resilient arm 103. The longitudinal arm112 may be shaped, as known in the art, such that it maximizes theshielding of the exposed area of the needle shaft of the hollow needle303 in front of the front side 107. It may, for example, be box-shapedwith the broader side facing the hollow needle 303. The longitudinal arm112 may be static or resilient. It is preferably resilient in order toallow facile production of the needle tip shielding device 100 in onepiece by e.g. molding. The longitudinal arm 112 is preferably nevercontacting the resilient arm 103 in order to not adventure the intendedfunction of the latter, i.e. its needle tip protective function. Thelongitudinal arm 112 may or may not contact the inside of the catheterhub 200 or the needle shaft of the hollow needle 303. It may, however,preferably never contact either of these.

In the claims, the term “comprises/comprising” does not exclude thepresence of other elements or steps. Furthermore, although individuallylisted, a plurality of means, elements or method steps may beimplemented by e.g. a single unit or processor. Additionally, although.individual features may be included in different claims, these maypossibly advantageously be combined, and the inclusion in differentclaims does not imply that a combination of features is not feasibleand/or advantageous. In addition, singular references do not exclude aplurality. The terms “a”, “an”, “first”, “second” etc do not preclude aplurality. Reference signs in the claims are provided merely as aclarifying example and shall not be construed as limiting the scope ofthe claims in any way.

1. A plastic needle tip shielding device comprising: a body with a rearside, a front side, an outer surface connecting said rear side and saidfront side, a hole extending from said rear side to said front side; anda resilient arm extending at an attachment point from said front side ofsaid body; wherein said resilient arm has a resting state, from which itmay be forced to yield free passage through said hole in an axialdirection of said body, said resilient arm being adapted for clamping aneedle tip of a hollow needle extending through said hole in a directionfrom said rear side to said front side, when said resilient arm is insaid resting state; and wherein any straight imaginary line extendinglongitudinally through said hole in the axial direction of said bodycoincides with said resilient arm, when said resilient arm is in saidresting state.
 2. The needle tip shielding device according to claim 1,wherein said body is shaped as a circular or distorted cut cone orcylinder.
 3. The needle tip shielding device according to claim 1,wherein said resilient arm comprises a back-hooking elongation, saidresilient arm together with said back-hooking elongation thereof havingan L-shaped form; wherein said any straight imaginary line coincideswith a point on the surface of said resilient arm in between saidattachment point and an inner corner in said L-shaped form of saidresilient arm, when said resilient arm is in said resting state; andwherein said any straight imaginary line coincides with saidback-hooking elongation, or with a point on the surface in between saidattachment point and said corner, when said resilient arm is clampingsaid needle tip in cooperation with said back-hooking elongation.
 4. Theneedle tip shielding device according to claim 1, wherein said resilientarm has a maximum of one external point of contact, said point ofcontact being a contact with any part of said hollow needle, when used.5. The needle tip shielding device according to claim 1, wherein theinner diameter of said hole is equal to or slightly larger than theouter diameter of the shaft of said hollow needle to provide a slidingand directing engagement between said shaft and said needle tipshielding device.
 6. A needle tip shielding device according to claim 1,wherein the needle tip shielding device is comprising a body shaped as acircular or distorted cut cone or cylinder with said rear side, saidfront side, said outer surface connecting said rear side and said frontside, said hole extending from said rear side to said front side, andsaid resilient arm extending at said attachment point from said frontside of said body; wherein said resilient arm has a resting state fromwhich it may be forced to yield free passage through said hole in anaxial direction of said body, said resilient arm together with saidback-hooking elongation thereof having an L-shaped form for clampingsaid needle tip of said hollow needle extending through said hole in adirection from said rear side to said front side; wherein any straightimaginary line extending longitudinally through said hole in the axialdirection of said body coincides with a point on the surface of saidresilient arm in between said attachment point and said inner corner insaid L-shaped form of said resilient arm, when said resilient arm is insaid resting state; wherein said any straight imaginary line coincideswith a point on the surface of said back-hooking elongation, or with apoint on the surface in between said attachment point and said corner,when said resilient arm is clamping said needle tip in cooperation withsaid back-hooking elongation; and wherein said resilient arm or saidback-hooking elongation has a maximum of one external point of contact,said point of contact being a contact with any part of said hollowneedle, when used.
 7. The needle tip shielding device according to claim1, wherein said needle tip shielding device is made of a molded plasticmaterial.
 8. The needle tip shielding device according to claim 1,wherein said outer surface is provided with at least one protuberance.9. The needle tip shielding device according to claim 1, wherein saidrear side is provided with a cone-shaped elevation through which saidhole is extending.
 10. The needle tip shielding device according toclaim 1, wherein said rear side is larger than said front side to forman inclination of said outer surface within the range from 0° to 10°.11. The needle tip shielding device according to claim 3, wherein thelength of said back-hooking elongation, measured from said corner to themost protruding part, is 0.5 to 6 times the diameter of said hole. 12.The needle tip shielding device according to claim 3, wherein the angleinside said corner is within the range from 60° to 110°.
 13. The needletip shielding device according to claim 1, wherein said body iselliptic.
 14. The needle tip shielding device according to claim 1,wherein said resilient arm of said needle tip shielding device isprovided with a back-dragging preventing elongation for prevention ofunintentional movement of said needle tip shielding device in thedirection from said front side to said rear side, when said needle tipshielding device is mounted in a catheter instrument.
 15. The needle tipshielding device according to claim 1, wherein said front side isprovided with a longitudinal arm for additional protective shielding ofsaid needle tip or said hollow needle.
 16. A catheter instrumentcomprising: a needle tip shielding device according to claim 1; acatheter hub and a needle unit; wherein said needle unit is providedwith connecting means for connection to said catheter hub, withconnecting means for connection to an external device, and is fixedaround the rear end of a hollow needle; and wherein said catheter hub isconnected to a catheter extending longitudinally in the same directionas said hollow needle when said needle unit is connected by saidconnecting means to said catheter hub.